OLED Drying Apparatus with Edge Gas Injection for Uniform Evaporation
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Solution Overview
Problem
The vacuum drying process in OLED device manufacturing results in uneven solvent evaporation rates between the edge and middle parts of the substrate, leading to morphological differences and display issues like Corner Mura due to preferential gas extraction at the edge of the vacuum chamber.
Innovation Solution
A drying apparatus with a pressure-reducing and pressure-regulating assembly that includes an extraction pipe and a gas-guiding pipe to equalize gas extraction rates by injecting an inert gas into the edge part of the cavity, ensuring consistent evaporation rates across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas extraction is performed at the edge part of the vacuum chamber first, then the drying speed at the edge part is improved, but the drying uniformity deteriorates causing Mura defects
Solution Approach 1:
The patent applies local quality by introducing different gas extraction rates at different locations within the vacuum chamber. The edge part has a higher extraction rate to accelerate solvent removal, while the middle part has a lower extraction rate to prevent excessive drying. This location-specific extraction strategy resolves the contradiction between improving edge drying speed and maintaining overall drying uniformity.
Solution Approach 2:
The patent changes the extraction rate parameter spatially across the vacuum chamber. By adjusting the extraction rate from the cavity at different locations, the system optimizes the balance between drying speed and uniformity. The extraction rate is increased at the edge part to improve productivity while being controlled at the middle part to maintain manufacturing precision.
2Reliability
If vacuum drying is performed to remove solvents, then the film formation is improved, but the drying uniformity deteriorates due to edge preferential extraction
Solution Approach 1:
The patent implements local quality by creating spatially varying extraction conditions within the vacuum chamber. The edge part experiences higher extraction intensity to ensure complete solvent removal and proper film formation, while the middle part experiences moderate extraction to maintain uniformity. This localized approach ensures reliable film formation throughout while minimizing Mura defects.
Solution Approach 2:
The patent modifies the extraction rate parameter at different locations to balance film formation quality and drying uniformity. By changing the extraction rate from the cavity at the edge versus the middle, the system achieves both reliable film formation and acceptable uniformity, resolving the contradiction between these two requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures uniform drying morphology across the substrate, preventing display defects by synchronizing gas extraction and injection to maintain equal pressure and evaporation rates, thereby enhancing the luminous efficiency and lifespan of OLED devices.
Implementation Method 1
solvents in the printed ink (hereafter 'ink') are evaporated under vacuum
Implementation Method 2
evaporated under vacuum to form a solid film
Implementation Method 3
the gas-guiding pipe is configured to supply a second gas into the edge part of the cavity
Data Source
AI summary
The present disclosure provides a drying apparatus and a drying method using the same; the drying apparatus includes a housing, a supporting assembly, a pressure-reducing assembly, and a pressure-regulating assembly; the housing includes a drying chamber; the supporting assembly is disposed in the drying chamber and has a cavity, and the cavity includes a middle part and an edge part surrounding the middle part; the pressure-reducing assembly includes a extraction pipe communicated with the cavity; the pressure-regulating assembly includes a gas-guiding pipe communicated with the edge part; and the pressure-reducing assembly extracts a first gas from the cavity and the gas-guiding pipe is configured to supply a second gas into the edge part of the cavity.